Pronterface won't connect to RAMPS 1.4

I have been having trouble getting Pronterface to connect to my RAMPS 1.4/Arduino Mega. When I try to connect, the monitor just says "connecting...", and when I unplug my board, I get the following error:

[ERROR] Can't read from printer (disconnected?) (SerialException): call to ClearCommError failed
[ERROR] Can't write to printer (disconnected?) (SerialException): WriteFile failed (WindowsError(22, 'The device does not recognize the command.'))
[ERROR] Can't read from printer (disconnected?) (SerialException): call to ClearCommError failed
[ERROR] Can't write to printer (disconnected?) (SerialException): WriteFile failed (WindowsError(22, 'The device does not recognize the command.'))
[ERROR] Can't read from printer (disconnected?) (SerialException): call to ClearCommError failed
[ERROR] Can't write to printer (disconnected?) (SerialException): WriteFile failed (WindowsError(22, 'The device does not recognize the command.'))
[ERROR] Can't read from printer (disconnected?) (SerialException): call to ClearCommError failed
[ERROR] Can't write to printer (disconnected?) (SerialException): WriteFile failed (WindowsError(22, 'The device does not recognize the command.'))
[ERROR] Aborting connection attempt after 4 failed writes.
[ERROR] Can't read from printer (disconnected?) (SerialException): call to ClearCommError failed

I have made sure that Pronterface and Marlin are using the same baudrate and serial port, and that the Arduino IDE is closed when I try to connect.
I have bought a brand new Arduino and Ramps board, still doesn't work.

Here is my config:
https://pastebin.com/zDemtR2B

Have seen that the serial baud rate should be

#define BAUDRATE 115200

Quote from here
[reprap.org]

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Computer Programmer / Electronics Technician

Just changed it, still no luck. Does the board need to be connected to the power supply in order to connect?

Usb power is enough to talk to it